Renewable electric fuse



`Nov. 13, 1923. l

' R.y G. SANDS RENEWABLE ELECTRIC FUSE Filed Nov. 22, 1920 Patented Nov. 13, 1923.

UNITED STATES PATENT oEEicE.

ROY G. SANDS, 0F CHICAGO, ILLINOIS, ASSIGNOR 'llO COOK VOF CHICAGO, ILLINOIS,

ELECTRIC COMPANY,

A'CORBORATION OF ILLINOIS.

RENEWABLE ELECTRIC FUSE.

Y `Aplnlieation filed November 22, 1920.

To all wlmi/2f t may concern.' y

Be it known that I, RoY'G. SANDS, a citizen of the United States, residing at Chicago, in the county of Cook and State of Illinois, have invented new and useful Improvements in Renewable Electric Fuses', of which the following is a full, clear, concise, and exact description, reference being had tothe accompanying drawing', forminga part of this specification.

My invention relates to electric fuses and it has special reference to fuses that are known as enclosed renewable fuses.

l\/ ore particularly my invention relates to an improved electric fuse in which the chamber lcontaining the fusible element communicates with the outer air through a restricted passageway comprised in a washer and of such form that the gases generated by the vaporization of the fusible elementv are properly vented from this chamber, but the flame thustocfcasioned is precluded from extending exteriorly of the fusefby reason of said venting passageway. To meet the Fire Underwriters specifications, an kenclosed renewable fuse must wholly confine the flame at the time of the vaporizationrof the fusible element to the interior of the fuse so that by no possibility may fire be projected exteriorly of the fuse. d

An object, therefore, ofmy invention is to provide a reproof enclosed renewable fuse which comprises elements that may beY recurrently used with the exception of the fusible element. y

Another object of myinvention is to provide a fuse of the character indicated above `in which the passageways serving to vent the fuse for expelling the gases from the interior thereof may be maintained permanently open and substantially free from clogging deposits which tend toform from the vapors generated at the time of the exploding of the fusible element. V

A further object of my invention is to provide a fuse as described` above in which a venting tortuous passage-way is formed in a washer of a unitary structurey that-permits of the gases being vented through the washers without the possibility of any flame being projected exteriorly of the fuse. The unitary structure of my washer allows of the ready assembling ofthe fuse and the expeditious renewing of the fusible element ythe venting washer of my at its ends 4,

-8 which is beveled,

serial No. 425,648.

As a result of the use of present invention, no danger or likelihood exists of the fuse being wrongly assembled whereby the venting passage-way may be permanently closed. For a better understanding of the nature and the scope of my `invention reference ma be had tol the` following description and the accompanying drawing, in which F ig. l is a view, partially in elevation and partially in section, of an enclosed renewable fuse constructed in accordance with my invention Fig. 2 is a disassembled view showing in detail portions of the several elements comprising the fuse of Fig. l;

Fig. 3 is a cross sectional view of a portion of a fuse comprising a knife-blade terminal and embodying a form of my invention, and

Fig. a is a modified form of a fuse having a removable washer of the general character illustrated in Figs. l and 2 but in which the removable cap is not secured thereto by means of a screw, as is shown in the structures of Figs. l and2. y

vReferring to Figs. ll and 2, a fusible element l of a usual form is contained within an insulating shell 2 that serves as the casing of the fuse. The fusible element 1 is slotted as shown at 3,v the ends 4 being bent at right angles and, in the assembled structure, being interposed between the upper face of a washer 5 and the inner face of an end cap 14. The washer 5 is a built-up unitary structure comprising 6, a core 7 and a face plate 8. The shell member 6 is provided adjacent to its upper end with a series of circumferentially arranged and spaced openings 9. The lower end of the shell 6 is provided with an opening, as shown in Fig, l, through which a shank portion 10 of the core 7 may project. In assembling the washer, the core 7 is extended through the opening in the face plate as shown. The upper edge of the core is then swaged to make a tight t between the core v7 and the face plate 8. The shank 10 is then projected through the opening formed in the shell 6 and is peened to firmly hold the core 7 in xed position. The core 7' is provided with a longitudinally extending opening 1l that is inafter exploding.

an exterior shell member Ll l) teriorly threaded at its lower portion. A narrower longitudinally extending :opening 12 extends itrom the opening l11 to a transverse bore 13 that is .formed adjacent to the shank portion 10. ln this manner the transverse bore 18 communicates with the opening 11 through the restricted passageway 1Q. The built-up washer 5 is, in this manner, assembled into a unitary structure of permanent roi-1n.

.lr series ot tortuous passageways tor venting the interior ol.' the fuse through the open ings 9, 12 and 13 is 'termed in the washer by reason ou the annular space 11 between the exterior ol" the core i and the interior oi' the enveloping shell 6.

Qin end'n cap 111 is interiorly threaded to engage the exteriorly thri-aded end ot the insulating shell i2. \.t its center portion. the cap 1l is counter sunk and provided with a central opening 15 through which the shank ol: a holding screw 16 may freely pass. The end oi the shank is threaded to enga-ge the thread tormed in the core 7 at the lower end ot the opening 11. The head ot the screw 16 is received in the countersunk portion ot the cap 14e. The screw '16 is provided with a. longitudinally .Xtending opening 1T that may be oft the same bore as the opening 1Q. The opening 17 also registers with the opening 12 thereby torniing a restricted passageway to the exterior otithe fuse. The screw 16 serves to l'irmly retain the end et ot the fusible element in close contact between the cap 14rand 'the washer 5. The exposed 'tace oit the head of the screw 16 is transversely slotted at 16L 'whereby the screw may be conveniently engaged with a proper instrument when it is desired to replace Athe fusible element. 1.

lVhen the Vfusible clement 1 is vapori/lcd. the gases resulting therefrom and contained within the Ytuse chamber ol the shell are vented through the restricted and tortuous passageways which open into the inse chamber through the openings fl YFormed in the shell 6 el' the washer 5. The openings S) severally communicate through the annular space 11`r the transverse bore 1S and the opening 12 with the opening 1T termed in the screw 16.y which opening directly communicates with the outer air.

.lt has been found that the deposits resulting 'from the gases occasioned by the vaporlization ot the 'fusible element do not substantially clog the if'enting passageways mentioned above. As a consequence thereof.A my present fuse may be repeatedly renewed and used without having its venting properties impaired while7 at the same time, tire and `llame resulting trom the vaporization ot the fusible element are precluded 'from VFollowing the gases and extending exteriorly o1 the iliuse. Furthermore il at any time the passages should become deformed or obstructed in any way by portions o1? the melted fuse, thel washer may be replaced as a unit, the tortuous passageway being through and within the washer and 1ndependent ol the shell structure.

ln Fig. 2l, an end cap 1% cooperates with a terminal member 18 that is provided with a knife-blade extension 1S). The member 18 is retained in position by the threaded cngagement olI the rap lit with theI shell 2. i\. screw 16fL is, in this instance, ollset :from the center line o'l' the l'use but the unitary washer is generally oit the same construction as the washer ot Figs. l and 2 except vlor the obvious inodit' 'ations xicceasitated by the oll'setting oit the screw 16'. The ventA ing in this ituse is likewise accoinplished through the openings il lormcd in the .enveloping shell member 6 ot the washer.

The easing 2 ot the ituse illustrated in Fig. 1 is provided at its end with a metallic ilferrule 1S) which is a common torni olZ construction. 'The core member T" o1 the unitary washer 5b is provided with a longitudinally extending opening 12" ot uniitorni bore and is enclosed in a shell 6". The opening 12h registers with the opening l-3 formed in the bent-over end et olf' the 'fusible element 1 and a correspondingly located opening 21 formed in the end cap 141. The exterior ot the core T" is provided with a series ot annular projecting tins "22 whereby the gases emanating trom thc shell 2 may he quickly cooled before entering into the openA ing 12b which is in direct communication with the outer air. The bent--over end #L oi? the fusible element 1 is irmly held intermediate the cap 141 and the washer 5" without the need oit a retaining screw, such as the screw 16 ot Figs. 1 and vWhile l. have 4described in detail several embodiments o'l my invention it is to he understood that l desire only such limita tions to he imposed `thereupon as are dictated by the prior art and specil" 'ally set `forth in the claims` 'forming a part ol this speeilicaA tion.

lil'aving thus described my invention what l now claim as new and desire to secure bv Letters Patent is: l

1. Aan enclosed electric inse comprising a washer oit' unitary structure having a defined tortuous passageway 'formed therethrough for restricting the venting ot' the associated electric fuse.

Q. An enclosed electric liuse. comprising a shell memberI` a renewable `fusible element, a removable` 'washer engaging said shell member and "fusible element, and a cap meinber engaging the end of' said shell member, said washer `being` ot unitary structin'e and having a tortuous and restricted passage* way formed therethrough 'tor venting said fuse.

3. An enclosed electric. lusc con'iprising a shell mcn'iber` a removable washer, and a cap member, said washer being a unitary structure and having a defined tortuons passageway formed therethrmigh through which rommunication is afforded between the outer air and the interior of the fuse.

4t. An enclosed electric fuse comprising a shell member-,a removable washer of unitary structure. and an end cap, said fuse being vented through a tortuous passageway formed within said washer.

5. An enclosed electric fuse comprising a shell member. a renewable fusible element. a removable washer. and a terminal member. said iasher being a unitary struc-ture and having a tortuous path formed therethrough which communicates with openings formed in said fusible elementl and said terminal member.

(3. A washer for a renewable electric fuse comprising an outer shell member, and an inner core member enveloped thereby but spaced to form an annular passageway, each of said members having openings fori'ned therein which, in the aggregate, constitutes a restricted tortuous path comprising said annular space.

T, A washer for an enclosed fuse comprising a shell member, a core member spaced therefrom to form an annular passageway, and a face plate, said shell member having an opening formed therein to communicate with said annular passageway and said core member having an opening that likewise communicates with said annular passageway and the outer air.

8. A built-up washer for lan enclosed fuse comprising an exterior shell member and a core member contained therein but .spaced therefrom to form an annular space, said shell member having an opening formed therein which communicates-'with said annular space at the opposite end of said lshell member, the opening formed in said core member a lfording communication with the outer air.

9. An enclosed renewable electric fuse comprising a shell member, end caps therefor, a renewable fusible element of greater length than and extending through said shell member, and removable washers at the ends of the shell member, said washers abutting said end caps and the ends of said fusible element overlapping the exposed faces of vthe washers and having contact with the inner faces of the end caps when the latter are in position, and said washers being unitary structures having tortuous venting paths formed therethrough for venting the fuse.

10. An enclosed renewable electric fuse comprising a shell member and end caps therefor, a renewable 'fusible element of a renewable fusible element,

greater length than and extending through said shell member, and removable washers at the ends `of the shell member, said washers abutting said end caps .and the ends of the fllsible' element overlapping the exposed faces :of the washers and having contact with theinner faces of the end caps when in posititon, and said washers having tortuous passage-ways formed therethrough through which communication is afforded for the fuse with the outer air.

ll. An enclosed electric fuse comprising a shell member, end caps therefor, a renewable fusible element of greater length than and extending through said shell member, and a washer `at one end of the shell meinber which is held in abutting relation to the corresponding end cap, an end of the fusible clement overlapping the outer face of said washer and beingheld in position therebetween and the inner face of the abutting end cap when the latter is in position, and said washer having a tortuous path formed therethrough through which the fuse may be vented and forming a supporting means for the fusible element whereby said fusible element may be positioned prior to the placing of the end cap in position.

l2. An enclosed electric fuse comprising a shell member, end caps therefor, a renewable fusible element of greater length than and extending through said shell member, and a washer at one end of the shell member which is held in abutting relation to the corresponding end cap, an end of the fusible element overlapping the outer face of said washer and being held in position therebetween and the inner face of the abutting end cap when the latter is in position, and said washer being a unitary structure within which a tortucus venting path for the fuse is formed and serving as a supporting means for the fusible element whereby the fusible element may be positioned prior to the placing o-f the end cap in position.

i3. An enclosed electric fuse comprising a shell member', removable washers fitted against the ends of the shell member, a fusible element extending through the shell member and having its ends bent over and in engagement with the outer faces of the washers, and end caps for the shell member which when in position serve to hold the ends fof said fusible element in Contact with the washers, each of said washers having a tortuous passage therethrough for venting the fuse.

l/l. An enclosed electric fuse comprising a shell member, removable washers fitted against the ends of the shell member, a fusible clement extending through the shell member and having its ends bent over and in engagement` with the outer faces of thc washers and end caps for the shellmember 'hioh when in position serve to hold 'tho In Wit-noso whereof have hereunto S111 @nds of sind fusible Clement in Contact with Smil'wd my nmno. tho wusshoxs, onoh of fluid mnshmf: being 1'0- nlovnrlo und hzwng n, Hntzny Sti'mtmo R( )Y G. SANDS.

5 within 'which :L i'oruoug venting 'lmfth is VVitnesses:

'I'ol'nlod .lm'. affords Hasta-'lated (w'nnrnnncn- GEO. R. FOLDS, Non 'for' the 'iuSo wll'h the outer 1m". J. C. Boom. 

